Supervisory control system



June 6, 1933. K. FALCK Er AL 1,912,935

SUPERVI SORY CONTROL SYSTEM Filed Dec. 2, 1926 2 Sheets-Sheet 1 Sfop Keg 7a3/er- Con/'ro/ U33 /35 e Kefgs WITNESSES: F /INVENTORS/ A Uf' ck n S /fn a a Jos/'ah tlg/(ner @coda/e 'ATTORNEY June 6, 1933. K. FALcK Er Al. 1,912,935

v SUPERVISORY CONTROL VSYSTEM l Filed Dec. 2, 1926 2 Sheets-Sheet 2 272 i275 VZ716 Patented June 6, 1933 UNITED STATES PATENT OFFICE KNUT FALCK AND JOSIAH ELMER GOODALE, OF FLUSHING, NEW YORK, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, ACORPORATION F PENNSYLVANIA SUPERVISORY CONTROL SYSTEM Application filed December 2, 1926. Serial No. 152,288.

Our invention relates to remote signalling systems and more particularly to that class known as sul'iervisory control systems.

An object of our invention is to provide means for synchronously switching a plurality of signalling lines, connecting two stations, from unit to unit at each end of the lilies.

Another object of our invention is to pro.-

0 vide means for restoring synchronously operating switches at two remote stations to their normal positions should they fall out of synchronism with each other.

Still another object of our invention is to provide means for instantly opening all signalling lines connecting two stations of two synchronous switches should they fall out of synchronism.

Another object of our invention is to provide a. simple anti-pumping apparatus which .shall function as common equipment for all apparatus units.

Another object of our invention is to provide means for simultaneously selectively controlling a plurality of remotely disposed apparatus units. n

There are other objects of our` invention which, together with the foregoing, will appear in the specification which follows In general our invention comprises a first station and a second station remotely disposed from each other, and connected by a plurality of signalling lines provided with a plurality of switch banks operating synchronously at each station to sequentially switch the signalling lines from unit to unit at each station. Means are provided for restoring the switches to their normal positions when they become non-synchronous, and the signalling lines are maintained open during this period. At the oilice end, relays connected in a novel circuit provide common anti-pumping equipment, these relays being connected between the switches and the signalling lines.

Referringl now to the drawings,

Fig. 1 is a diagram of the apparatus and circuits at the office and Y F ig.'2 is a diagram of the apparatus and circuits at the substation.

In practicing our invention we provide a plurality of signalling lines 16-18 connectf ing two stations and arranged to beswitched synchronously from key 101 to key 130 at the office and from unit 236 to unit 248 at the station by switch banks 152 to 162 at the oiiice v and switch banks 201 to 207 at the substation.

synchronism between the switches for restoring them to normal.

Referring moreparticularly to Fig. 1, unit 101 is an individual operating key for controlling three-phase circuit breakers located at a remote station. A stop key 102 individual to each of the remote units to be controlled is connected in a circuit for bringing the switches to a stop at any desired selecting position. Lamps 109 to 114 respond to supervisory signals for indicating the position of each of the circuit breakers. The relays to 120 are the supervisory receivers. Similar equipment is disclosed for another individual apparatus unit. The key 146 is a master key and the key 147 functions to start operations.

Each of the contacts of the switches 153 and 151t is associated with individual operating keys, switch 154 being connected to the trip contacts of these keys and 153 to close contacts. The contacts of switch bank 152 are connected to individual keys on their stop contacts and function to determine the stop position of the switches corresponding to the operated key. The switch banks 155 to 160 direct the supervisory signals, the odd numbered banks controlling tripped superviA sory indications, and the even numbered banks controlling closed supervisory indications. Each pair of switch banks, such as 155 and 156 may be associated with an individual power system, although for purposes of illustration are shown connected to individual phases of a system.

The switch bank 161y controls circuits for stopping the switches at their normal position, should the switches at the two stations fall out of step. After a complete cycle of operations, when the switches have reached their twenty-fifth contact, bank 161 stops them on their first position. The switch bank 162 controls circuits for detecting the positions` of' the switches to control the relays which are to restore the switches to normal, following a non-synchronous condition.

Relay 20 is the line relay connected in the drive circuit 12 and intermittently energizcs and deenergizes as the line closes and opens. It, in turn, intermittently operates the stepping magnet 195 of the switches 152 to 162. The relay 193 is connected in the check circuit 13. It the switch wipers ot the two stations are in synchronism, no current flows over this line, and the relay 193 remains decnergized. A non-synchronous condition, however, energizes the relay 193. The relay 194.` maintains the signalling lines l-l to 1S normally closed except upon a non-synchronous condition when the signalling lines are instantly opened thereby.

The relay 10 operates responsive to a nonsynchronous condition ot the switches to open the normal operating circuit for the stepping magnet 195 and substitute therefor a selfopening circuit so that the switches are stepped to their normal position. Relay 199 is the start relay energized upon the closing ot a start key tor starting the switches into operation. The relays 197 and 19S are electrically interlocked to periodically open and close the drive circuit for stepping the switches from contact to contact.

The relay 196 encrgizes when the switches have reached the predetermined stop position and maintains the drive circuit open. The relays 190 and 191, 178 and 179, 181 aud 182 are interposed supervisory receiving relays, each pair being individual to a phase and one ot each pair being responsive to close supervisory signals and the other to trip.

The relays 163 to 167 and 1S() are the interposing anti-pump common equipment. The relay 163 operates in response to a closing circuit breaker7 control operation to prepare the anti-pumping circuits. Relay 165 is the receiving relay to receive the supervisory closed signal which thereby indicates that the circuit breaker has been closed and, therefore, that closing energy need no longer be transmitted. The relay 166 operates in response to the energization ot relay 165 'for opening the closing control circuit, and the relay 167 energizes to prepare a circuit for the relay 165.

The relay 180 functions in response to the closing of a three-phase circuit-breaker key to connect the receiving supervisory relays in multiple to the anti-pumping receiving relay 165.

Referring now more particularly to Fig. 2, the switch banks Q01 and Q02 are the control close and trip banks, respectively, while switch banks 203 and 205 are the supervisory switch banks for each of' the three-phase systems. Switch bank 9.06 controls circuits for restoring the switches to normal upon a nonsynchronous condition and the switch bank 207 controls circuits tor detecting the positions of the switches.

Relay 208 holds the signalling lines 14 to 1.8 normally closed over armatures 214v to 210 during the synchronous condition of the switches and instantly opens them upon a non-synchronous condition. rlwhe relay 209 is connected in series over the line .13 for detecting a non-synclnonous condition. The relay is connected in series over the drive circuit 12, periodically energizing and deenergizing as the line closes and opens and it, in turn, periodically energizes and deeuergizes the stepping magnet Q19 of the switches Q01 to 297. The relay c25 energizes responsive to a non-synchronous condition tor closiug a self-opening circuit ot' the stepping magnet 219. The relay 226 energizes to open the locked start circuit at the end of the cycle oi operation when the switch wipers have reached their twenty-lifth contact.

The relays 229, 231 and 2232 energize in response to the automatic operation ot a circuit breaker for starting the switches into operation. The relay Q3() prepares a restart circuit should a circuit breaker change its operation durin the oiiieraliou oi the switches, and the relays Q27 and 22S operate as vibrators for periodically opening and closing the driving circuit. Units 36 and Qel-S are examples ot' individual circuit breakers controlled by the individual equipments Q33, Q34 and Q21, 229, respectively. The circuit breakers may be automatically operated because ot changes in the power line conditions.

In order that the invention may be better understood, a detailed description will now be given ot the operations which take place when the dispatcher desires to operate a circuit breaker and when a circuit breaker automatically operates.

It will be assumed that the dispatcher desires to ope 'ate the circuit breaker 24S from its tripped to its closed position.

Normally, a holding circuit is completed for maintaining the relays 2O and 224 euergized. This circuit is completed from ground through the battery, the closed Contact of the master key 146, the armature Q1 and its back contact, through the winding of inlay 20, drive circuit 1Q, winding of relay 221 and the back contact and arn'iature 270 to ground. Energizatiou of the relay Q0 at the otlice opens the energizing circuit tor the stepping magnet 195 at armature 2Q.

The relay 19S is normally energized over a circuit from ground through the battery, through the winding ot relay 198, the back contact and armature Q3 to ground. The energization of the relay 198 over the circuit Vmagnet 219 at armature 264 and opens an obvious energizing circuit of the relay 230 at armature 265. The relay 228 1s normally energized over a circuit from ground through ythe battery, winding of relay 228 and the back contact and armature 273 to ground. The energization of the relay 228 opens an obvious energizing circuit for the relay 227 at armature 271.

In order to close the circuit breaker 248, the dispatcher will operate stop key 135 to close Vitscontact and the twist key 130 to move it counter-clockwise, thereby ciosing its righthand contact and `also operate the start key 147 to its closed position. As a result of the Voperation of the startkey, a circuit is completed from ground over the upper contact of the start key 147 and through the winding of relay k199 and the battery to ground.

The energization of the relay 199 over the circuit just traced completes a locking circuit for itself at armature 124 over a circuit from ground through the battery, winding` of ,relay 199, the armature 24 and its front contact and back contact and armature 25 to ground, A further result of the energization of relay 199 is to open the energizing circuit of-the relay 198 at armature 23. After an interval of time, the relay 198, which is a slow-.release relay, closes a circuit for the relay 197 at armature 24 and its back contact. The relay 197 energizes and completes an energizing circuit for the relay 198 from ground over the front contact and armature 55, the back Contact and armature 26 and through the winding of relay 198 and the battery to ground. The drive circuit is thus opened at armature 21.

As a result of the opening of the drive circuit at arlnature 21, the relays 20 and 224 are ,denergized The deenergization of the relay 20 closes an energizing circuit for the stepping magnet 195 over a circuitfrom ground through armature 22 and its back contact, back contact and armature 27,

vlocking circuit for itself from ground .through battery, winding of the relay 230, `armature 275 and its front contact and the vback contact and armature 268 to ground.

A further result of the energization of the relay 230 is to prepare a locking circuit for the re-start relay 232 at armature 274, and to open the circuit of the start relay 231 at armature 276.

The deenergization of relay 224 noted above completes an energizing circuit/for the stepping magnet 219 over a circuit from ground through armature 264 and its back contact, the back contact and armature 267, 'through the winding of the stepping magnet 219, and battery to ground. rlhe stepping magnet 219 energizes to prepare its pawl for stepping the wipers :from their first to their second contact. i

It will be recalled that, in addition to the operations enumerated above, the energization of the relay 197 completed an energizing c' cuit for the relay 198. Upon the energization of the relay 198, the energizing circuit for the relay 197 is again open at armature 24. Relay 197, being a slow-release relay, permits its armatures to drop to their back pesitons after an interval of time. As a result of the armature 21 closing its back contact, the original circuit over the drive line is again completed, and the relays 20 and 224 are again energized. The energization of the relay '20 opens the circuit of the Steps ping magnet 195 at armature 22, and the stepping magnet is deenergized, whereupon its pawl steps the wipers of the switch banks 152 to 162 from their first to their second contacts.

At the substation, the energization of the relay 224 opens the circuit ofthe stepping magnet 219 at armature 264, and the stepping magnet is dcenergized, thus stepping the wipers of the switch banks 201 to 207 from their first to their second contacts.

Upon the deenergizationof the relay 197, the energizing circuit of the relay 198 is again opened at armature 55, and this slowrelease relay deenergizes. After an interval of time, it again completes an energizing circuit for the stepping magnet 197 which thereupon opens the drive circuit at armature 21, and the cycle which is described abovein detail Ais again repeated. In this manner, the switchesat the office and the substation are stepped from contact to contact.

It will be noted that, when the wiper of the switch 162 is on an odd numbered contact and the switch wiper of switch 207 is on an odd numbered contact, there is no current flowing over the conductor 13, it being grounded at both ends. The circuit may be traced from ground over the back contact and. the armature 28 through any one of the odd numbered contacts of switch bank 162, its wiper, through. the winding of relay 193, conductor 13, the winding of relay 209, any one of the odd numbered contacts of switch bank 207 and the armature 216 yto ground. Neither relay 193 nor 209 is, therefore, en-

ergized. Similarly, with the switch wipers 162 and 20T on any even numbered cont-act, no energizing circuit is completed for the aboye named relays, the circuit being conipleted from the negative side ot the battery at the oliice through an even numbered contact and the windings ot' relays 193 and 299 in series with the conductor 1S to the negative side of battery over any one of the even numbered contacts of switch banlr 20T at the substation. 'lheret'oreI` with wipers at the two stations in synchronisin. relays 193 and 299 remain dcenergized.

It, however. the wipers at the ofice, for any reason, fall out of step ith those at the. substation, an energizing circuit is completed, from ground at either station and through the. windings of relays 193 and 209 in series over conductor 13 through the battery at the other station. Thus, it the wipers tall out of step with the switch wiper 1(32 on an odd numbered contact and out ot step with the switch Wiper 207 on an even contact, a cireuit is completed from ground at the oliice through the battery at the substation, or, assuming the only alternative condition, if the wiper falls out of step While on an even position at the otlice and on an odd position at the substation, a circuit will be completed from thel battery at the otlice to grouml at the substation.

It is evident, ol course, that these switch wipers may tall two steps out. ot synchronisni with each other, in which case, a condition similar to that which prevails when the wipers are in synchronisni will exist, However, in actual practice, it has been found impossible to deliberately torce these switches two steps out ot synchronism, since the relays operate with such speed that, as soon as they fall one step out of synchronism, the condition noted above takes place.

It' the switch wipers tall out ol step as noted above, an energizing circuit is conipleted for the relay 194A over a circuit from ground to the front contact and armature and through the winding ot relay 194 and the battery to ground. The energization of relay 191 immediately opens all of the signalling lines 11 to 18. thereby preventing any false signalling, either of control or ot supervision, during a non-syiichronous condition of the switches.

A further result ot the cnergizatimi ot relay 193, due to the non-synclnoniais condition, is 'to complete an energizing circuit for the relay 10 'troni ground over the l'ront Contact and armature 30 through the winding of relay 10, and the battery to ground. The encrgization ot the relay 1() completes a locking circuit tor itself from ground to battery through winding oi" relay 10, liront. contact and armature 31 and the back contact and armature 25 to ground.

A further result of the energization of relay 10 is to open a normally operating circuit ot the stepping magnet 195 at armature 2T and to complete aperiodically operating circuit for the stepping magnet which is cornpleted from ground through the wiper ot' switch bank 161 through the back contacts of theI stepping magnet, the front contact and armature 27 through the winding of the stepping magnet 195, and the battery to ground. The stepping magnet 195, upon energization, opens its own circuit at its back contact, thereby deencrgizing to step the wipers to their next contact. In this manner, the wipers are rotated from contact to contact. it the substation, upon energization of the relay 209, a circuit completed for the relay 20S from ground over the front Contact and armature 217, through the winding of relay 298 and the battery to ground. rl`he relay 208 is energized and completes a locking circuit tor itseltl from ground to battery, through the winding of relay 208, front contact and armature 215, and back contact and armature 268 to ground. As a result of the energization oi' the relay 208, the signalling` lines are open at armatures 210 to 214.

A further result ot the cnergization of the relay 209 is to complete an energizing circuit for the relay troni ground over the front contact and :miniature 218 and through the w i ndingol relay 225 and the battery to ground. rthe energization of the relay completes a .locking circuit for itselt from ground to battery, through the winding of relay 225, over the front Contact and armature 266 and the back contact and armature 268 to ground. The energization of the relay opens the normal stepping magnet energization circuit of the stepping magnet 219 at armature 267 and transfers it. to a periodically operating circuit over armature 267 and its front contact, the back contact and armature 220 of the stepping magnet 219, and through the switch bank 20o and its wiper to ground.

The energization ot the stepping magnet 219 opens its own circuit and thereby deenergizes this magnet to step the wipers to their next contacts.

Then the switch wipers reach their twentyditth contacts, an energizing circuit is completed at the oliice -for the relay 192, over the front contact of the stepping magnet 195 and the twenty-fifth contact and wiper ot switch 161 to ground. The energization ot the relay 192 opens the locking circuit of the relay 194 and relay 10. The deenergizat-ion otl relay 10 opens the stepping magnet circuit` and steps its wipers to their tirst contacts.

Similarly, at the. substation, when the switch wipers reach their twenty-fifth contact, the stepping magnet 219 is energized over a circuit from ground to battery through the winding of the stepping magnet 219, armature 267 and its front contact, and the contact k291 of the switchy 206 and its wiper, to ground. The stepping magnet,y upon energization, completes an energizing circuit for the relay 226from ground through the battery andthe winding of relay 226, front contact oithe stepping magnet 219 and contact 291 of the switch bank 206 andits wiper, to ground.

The energization of the relay 226 opens the locking circuits of the relays 208 and 225. The deenergizationof the relay 225 opens the 'circuit of the vstepping magnet lwhich there'- upon steps its Wipers to their' irst normal contact. In this manner, the apparatus of the two stations are restored to normal after a non-synchronous condition.

The relay`269 being deenergized, since the switch wipers are now in synchronism, relay 208 deenergizes and the signalling lines are again closed. The system is thus protected from false operations should the switch Wipers fall out of synchronism while, at the same time, the switches automatically restore themselves to their normal or iirst position. Since, in most cases, the falling out of synchronism is caused bysome temporary condition, Vthe'rule will be that, upon the next operation of the switches, synchronism and correct operation will be obtained.

It will now be assumed that the switches have operated in synchronism. When the switch wiper reaches its second position, a circuit will be completed from ground over the contacts of the stop key 135, conductor 30, through the second Contact of the switch bank 152 and its wiper and through the winding of relay 196 and relay 163 in multiple, and the battery to ground. It will be noted that conductor is grounded over a multiple circuit including armature 145 and the eX- treme right-hand contact of switch 130. Ordinarily, if it is desired that the switches be brought to a stop long enough only to operate the breaker, key135 is not operated and when the breaker operates, relay 142 is operated in a manner to be described `for remov ing ground from conductory 30 and the switches will continue to step.

The energization of the relay 196 opens the energizing circuit of the relay 198, atarmature 26 thereby preventing any further deenergization of the relay 197, and the drive line remains closed. The stepping magnet 195 can, therefore, no longer obtain an energizing circuit over the contacts of armature 22.

An operating circuit for closing the circuit breaker will, at this time, be completedfrom ground over the contacter master control key 136, through the contact 133 ofthe operate control key 130, conductor 31, through the second contact of the switch bank 153 and its wiper, the armature 170 and its front contact, the back contact and armature 175, back contact and armature 44, conductor 18, armature 210 and its back contact, the wiper and second contact of the switch bank 201 and through the Winding of relay 221 and the battery to ground.

The energization of the relay 221 completes an operating circuit for the closing solenoid 223 over armature 262 and its front contact. The energization of the solenoid'223 closes the circuit'of relay 255 to operate the circuit breaker 248. Upon the movement of 'the circuit breaker to its closed position, a circuit is completed `from ground over its .pallet contact 253, through the Contact 286 andy wiper of the switch bank 203, the front con- I tact and armature 212, conductor 16, armature 42 and its back contact, through the winding of relay 182 and the battery to ground. i

The energization of the relay 182 completes an energizing circuit for the relay 142 from ground over armature 188 and its front contact, the wiper and second contact of the switch bank 156, through the winding of ref lay 142 and the batterytov ground. l

The energization of the relay 142, as is VeX- plained in more detail below, operates to release the armatures 144 and 145 which, thereupon, close their lower contacts. The movenient of the armature 144 opens the energizing circuit of the lamp 1,39 and closes the circuit vof the lamp 140. The dispatcher is thus informed that his circuit breaker has been closed in accordance with his operation.

In parallel with the closing control circuit traced above, an energizing circuit is completed for the relay 167 from the key 130, conductor 31 through the second contact of the switch bank 153 and armature 170 and its front contact, as previously traced, through the winding of relay 167, armature 171 and its back contact and the battery to ground. The energization of the relay 167 completes a locking circuit for itself over armature 176, and prepares an energizing circuit for the relay 165 at yarmature 177. p

As a result of the energiza-tion of relay 182, a circuit is completed from ground over armature 188 and its front contact, the Wiper and second contact of the switch bank 156 and through the winding of relay 142 and the battery to ground. The energization of the relay 142 unlatches its armatures, as

described above. A further result of the energization of relay 182 is to complete an energizing circuit for the relay 165 from ground over armature 189 and its front contact, armature 177 and its front contact, through the winding o1 relay 165, the front contact and armature 168 and the battery to ground.

`The energization of the relay 165 completes a locking circuit for itselil from ground over the backvcontact and armature 17 2,y the front contact and armature 173, through the winding of relay 165 and the front Contact and armature 168 and the battery to ground. A

'lio

further result of the energization of relay 165 is to complete an obvious energizing circuit lfor the relay 166 over the -front contact and armature 171 and the front contact and armature 16S.

It will be recalled that the operating circuit for closing the circuit breaker was traced over the back Contact and armature. .1.75. Upon the energization ot the relay 166, the closing control circuit is opened at armature 175. It, therefore, the circuit breaker opens up for any reason, such as an overload. the dispatcher no longer has control over it to again close it until he irst operates the trip key for releasing the anti-pmnping circuit as will be described hereinafter.

In this manner, common equipment of a very simple nature is employed for preventing the repeated closing of a circuit breaker by the dispatcher, should he close upon a short circuit. An arrangement of this nature is necessary, the dispatcher being unable to tell how long it will be necessary for him to maintain energy on the line in order to close the circuit breaker, since he has no way ot' knowing when the circuit breaker is lat-ched and closed. Under such circumstances. if the circuit breaker closes on a short circuit, it will immediately trip but, since the dispatcher still has his control key closed, the circuit breaker will again start to close and this cycle will be repeated with detrimental effects upon the circuit breaker and the system.

By the arrangement described above, known as an anti-pumping system. as soon as the first supervisory signal is received, indicating a closed condition of the circuit breaker, the control line is automatically opened, and the dispatcher is thereafter unable to again close the circuit breaker except by first operating the trip key, as will be described hereinafter.

Upon restoring the key to normal,

- the energizing circuit for the relay 163. previously traced, is opened at the contacts of the key. The deenergization of the relay 163 opens theA energizing circuit of the relay 165 at the armature 168. Relay 165 deenergizes v to, in turn, open the energizing circuit of the relay 166 at armature 174. The deenergizat-ion oi" the relay 166 again prepares a control circuit over the back contact of armature 175, and the dispatcher may, thereupon, again perform a control operation.

Before these operations have been performed, he has been informed by the trip supervisory indication that the circuit breaker has tripped out, and, therefore, knows of existing possible trouble at the substation.

In order to trip t-he circuit breaker, it is merely necessary for the dispatcher to operate the key 130 clockwise and so to close its left-hand contacts. A circuit will, thereupon. be completed from ground over the contacts of the master control key 136 and through the contact 131, conductor 32, the second contact of the bank 154 and its wiper, the armature 169 and either its front or back contact, front contact and armature 43, conductor 17, armature 211 and its back contact the wiper and contact 284 of the bank 202 and through the, winding of the relay Q22 and the battery to ground.

The energization ot the relay Q22 completes an energizing circuit for the trip magnet 254 over armature Q63. Upon tripping, the circuit breaker will transmit a supervisory signal in the manner described above.

After all the desired operations have been performed and the dispatcher desires that the. switches be restored to normal, he will open the stop key 135. As a result of the opening of the st-op key, the energizing circuit of the relay 196 is opened. The deenergization of the relay 196 again completes an energizing circuit for the relay 198 as previously traced, which, in turn, opens the circuit of the relay 197, and these two operate, in the manner described above, to periodically open the drive line at armature 21, thus stepping the switch wipers from contact to contact.

lVhen the switch wipers reach their twentyfifth contacts and the stepping magnet is energized following the opening of the drive line, an energizing circuit is completed for the relay 192 over a circuit from ground to battery, through the winding of relay 192, the front contact of the stepping magnet 195, over the twenty-fifth contact and wiper of the bank 161 to ground. The encrgization of the relay 192 opens the locking circuit of the start relay 199 at armature 25. The relay 199 deenergizes to again complete a normal energizing circuit for the relay 198 at armature 23. The energization of the relay 198 holds open the energizing circuit of the relay 197, which, thereupon, closes the driving circuit at armature 21, and the relay 20 is energized to open the circuit of the stepping magnet 195.

The deenergization of the stepping magnet 195 operates its pawl to step the wipers from their twenty-fifth to their first contacts. In this manner, the switches are restored to normal.

The switches may also bc brought to a stop by operating key 146 when the switches have reached the desired position. Any of thc means now well known in the art, such as connecting a lamp to each contact of one switch in the bank in such a manner that as the Wiper moves over the contacts, the particular lamp connected to the contact becomes illuminated, may be employed to indicate thc position of the switches. This opens the circuit of line relays 2() and 221 and the stepping magnets remain energized until the key is again closed to energize the line relays.

If a circuit breaker automatically trips or changes its condition, a momentary energizing circuit is completed over the pallet contacts 249 and 250 of the circuit breaker 248 and through the winding of relay 232 and the battery to ground. The energization of the relay 232 completes an energizing circuit for the rela-y 231 over a circuit from ground through the armature 279 and its front contact, back contact and armature 276, through the Winding of relay 231 and the battery to ground. The energization of the relay 231 completes an energizing circuit for the relay 229 from ground over the front contact and armature 277, through the Winding of relay 229 and the battery to ground.

Relay 229, upon energization, locks its-elf, through armature 272 and thek armature 268, to ground. A further result of the energiza tion of the relay 229 is to open the normal energizing circuit for the relav 228 at armature 273. Relay 228, being a slow-release relay, deenergizes and, after an. interval of time, permits its armature 271 to close a circuit over its back contact for the winding of relay 227. The energization of the relay 227 opens the normal drive circuit at the armature 270 and completes an energizing circuit for the relay 228 at armature 269. Thereafter, relays 227 and 228 periodically open and close each others circuits, thus opening and closing the drive circuit 12 in exactly thel manner described in connection with the oilice. The switches at the otlice and the substation are stepped from contact to contact and, at each point, supervisory signals are transmitted from a circuit breaker to the office, as de-y scribed in detail hereinbefore. lVhen the circuit breaker, the condition of which has changed, is reached, a corresponding supervisory signal will be transmitted to the oiiice and the dispatcher will thus be informed of the change which has occurred.

Then the wipers reach their twenty-fifth contact and the stepping magnet is energized, a circuit is completed for the relay `226 from ground to battery, through the winding of relay 226, the front contact of the stepping magnet 219, contact 291 and wiper of switch bank 206 to ground. The energization of the relay 226 opens the locking circuit of the relay 229. The deenergization of the relay 229 closes the circuit of the relay 228 at armature 273, which, in turn, opens the circuit of the relay 227 at armature 271. The deenergization of the relay 227 again closes the drive circuit at armature 270, and the relays 224 and 20 are energized to open the circuits of their respective stepping magnets, which, thereupon, step their wipers to the iirst contacts.

If a circuit breaker' operates while the switchesare'in motion, a restart circuit is prepared in the following manner.

For illustration, it will be assumed that the circuit breaker 236 closes while the switches are in operation. As described before, a momentary circuit is completed for the relay 232. Viith the s vitches in operation, the relay 230 is energized over the hack contact of arn'iature 265 upon the first deenergization of the relay Upon the energization of the relay 230, a locking circuit is completed for itself over armature 275 and its front contact, and the back contact and armature 268.

Now, if the circuit breaker 236 closes, a momentary circuit is completed for the relay 232 as traced before. Upon the energization of the relay 232 a locking circuit is completed for the relay 232 from ground through the battery and the winding of relay 232, armature 278 and its front contact, and the front contact and armature 274 to ground. The relay 232 thus remains energized until the switches are restored to normal. At this time, the relay 226 is energized, as described in detail above. and opens the locking circuit of the relay 230. The relay 230, upon deenergization, opens the locking circuit of the relay Since relay 232 is a slow-release relay, a momentary circuit will be completed for the relay 231 over the armatures 279 and 276. The energization ot the relay 231 energiz'es the relay 229, which, in turn, locks itself and starts the switches into opeiation, as described in detail above. This prevents the loss of any supervisory signal should changes of circuit breakers take place while other signals are being transmitted'.

It is obvious, of course, that our invention' has application to many other forms of remote` signalling, as, for example, remote metering. As illustrated in the drawings, the receiving meters 150 and 151 at the oiices are connected to predetermined contactors on the selector banks while their associated transmitting meters 256 and 257 at the substation are connected to equivalent contacts. In the manner described in detail above, the switches may be rotated until the contact at which said meter 151 is connected is reached. Simultaneously, the switch at the substation will reacl; the contact associated with the meter 256 thereafter, and a direct circuit over the signalling line is completed. between the me'- ter 256 and the receiving device 151. The meter 256 is, of course, connected to measure an electrical quantity at the substation and, in the usual manner, as shown in the patent to White No. 1,614,222 for example, will transmit its indicator position to operate the in dicator of the meter 151 to an equivalent position. The dispatcher is thus informed of remote meter readings.

Although we have chosen to illustrate our invention as applied to a supervisory control system, it is obvious that it may be applied to any remote selective signalling sym CII tem and we intend to limit ourselves only insofar as set forth in the appended claims.

le claim as our invention:

l. ln a .simervisory control system, a lirst station, a second station, a selector switch at each ot said stations, apparatus units at said second station, operating means individual to cach ot said apparatus units at said lirst station for operating siid units, a control line connecting said stations, a supervisory line connecting said stations, means tor operating ysaid selector switches in synchronism, common electronnignetic equipment at said tirst station operaia-ie to open the control line, means including circuit, connections from said operating means whereby, upon the operation ot one ot said operating means, said common electro-magnetic equipment is conditioned tor operation in response to a signal over said snliervisin'y line, means including said selector switches and one ot said o'icrating means lor transmitting an impulse over said control line to said second station. means operated in response to said impulse :tor operating the apparatus unit associated with said operating means, means controlled by the operation oi said unit tor transmitting an impulse over said supervisory line` means resi'ionsiveto said impulse for operating said common electromagnetic equipment whereby said (mei-ating` means is rendered ineti'cctive to further control said apparatus unit in the event that said apparatus unit automatically returns to its original condition, and means tor restoring said common electro-magnetic equipment tobagain render said operating means et'- t'ectivc to reoperatc said apparatus unit.

ln a supervisory control system, a` lirst station. a second station, cont-rol and supervisory lines therebetween, apparatus units at said second station operable to closed and open positions, operating means individual to each ot' said apparatus units at said lirst station, a selector' switch at each ot said stations, means for operating said selector switches in synchronfsm to sequentially as sociate the operating means with their respective apparatus units, an electromagnet at said first station common to all ot said apparatus units tor controlling the connection ot' said operating means to said control line, electromagnetic means responsive to supervisory signals received over said supervisory line as a result of the operation of an apparatus unit to its closed position, said common elcctromagnet being responsive to the operation of said electromagnetic means Ator opening said control line whereby said operating means is rendered inetilective to further operate. said apparatus units, and means whereby said electromagnetic means is maintained operative thereafter independently ot superif'isory signals under the control of said operating means at said first station.

3. In a supervisory control system, a first station, a second station, a selector switch at each station, apparatus units at said second station, operating means individual to each ot said aplairatus units at said lirst station, a control line connecting .said stations, a supervisory line connecting said stations, means for operating said selector switches in synclnonism, means includingr said selector switches and one ot said operating means tor transmitting an impulse over said control line to said second station, electromagnetic equipment at said lirst station common to all ot lsaid operating means including circuit connections from said operatingr means to said common equipment whereby upon the operation ot said operating means said common equipment is associated with said supervisory line for operation in response to a signal over said supervisory line, meansl including circuit connections whereby said common electro-magnetic equipment controls the eli'ectivcness oi all ot' said operating means 'tor transmitting the impulses over said control line, means operated in response to the impulse over said control line tor operating the apparatus units associated with said operatingr means, means controlled by said unit 'lor transmitting an impulse over said simervisory line, means responsive to lsaid impulse vfor operating the conditioned common electro-nn1gnetic equipment, means controlled bv said common electro-magnetic equiinnent for opening the control line to render said (merating means non-opeative to further control said apparatus unit in the event that said aplnnatus unit automatically returns to its original condition, and means lor restoring said common electro-magnetic equipment to normal to again render said operating means operative to reoperate the apparatus unit.

-l. In a supervisory control system, a first station, a second station, a plurality of alltomatic circuit breakers at the second station, said breakers having closed and tripped positions, signalling devices at the lirst station individual to each circuit breaker, synchronous selectors at each ot' said stations, a control circuit connecting the stations, means including said synchronous selectors and said control circuit for selectively operating any one of said circuit breakers from the first station, common electro-magnetic means at the first station operable to render said means ineffective to selectively operate any one of said circuit breakers, and means responsive to the operation of a selected circuit breaker to the closed position for effecting the operation of the signalling devices associated with the operated circuit breaker and for effecting the operation of the common electro-magnetic means to interrupt the control circuit thereby to prevent the circuit breaker from being reclosed in the event it is automatically operated to the tripped position.

5. In a supervisory control system, a first station, a second station, a plurality of automatically-tripped circuit breakers at the second station, said circuit breakers having closed and tripped positions, a control circuit connecting said stations, operating means at'said first station individual to each of said circuit breakers for transmitting signalling impulse conditions over said control circuit to selectively operate said circuit breakers to closed and tripped positions, electro-magnetic means at the first station common to all of said operating means for directly controlling the operativeness of vall of said operating means to transmit said signalling impulse conditions, means responsive to the operation of a circuit breaker to the closed position by its operating means for operating said' common electro-magnetic means for interrupting the control circuit to render said operating means ineffective to further transmit signalling impulse conditions, and means operable to cause said common electro-magnetic means to reclose the control circuit.

6. In a supervisory control system, a first station, a second station, a selector switch at each of said stations, a plurality of automatically-tripped circuit breakers at the second station having closed and tripped positions, operating means at said first station individual to each of said circuit breakers, means for operating said selector switches in synchronism, a control circuit connecting the stations, means including said selector switches and said control circuit whereby any one of said operating means selectively control its associated circuit breaker from the first station, electro-magnetic equipment at the first station common to all of said operating means and having an armature connected in said control circuit whereby said common electro-magnetic equipment controls the effectiveness of said operating means for selectively controlling said circuit breaker, means controlled b the operation of any one of said circuit breakers to the closed position by its associated operating means for controlling said common electro-magnetic equipment whereby its armature is operated to render said operating means ineffective to further control the circuit breaker in the event that said circuit breaker is automatically tripped when closed, and means whereby said operating means is again rendered effective to reoperate its associated circuit breaker to the closed position.

7. In a supervisory control system, a first station, a second station, a plurality of automatically-tripped circuit breakers at the second station, said breakers having closed and tripped positions, operating means individual to each circuit breaker at said first station, Ia control circuit connecting said stations, synchronouslyoperated selectors at each of said stations` means including said synchronously-operated selectors said control circuit and one of said operating means for selectively controlling one of said circuit breakers at the second station, a common electro-magnetic means at said firststation responsive to the operation of any one of said circuit breakers to the closed position by its operating means, said electro-magnetic means having an armature connected in said control circuit and operable to prevent successive like closing operations of the same circuit breaker as a result of the single operation of said operating means.

In testimony whereof, we have hereunto subscribed our names this 18th day of November, 1926.

f KNUT FALCK.

JOSIAH ELMER GOODALE. 

